A dynamic multi-agent model was built in order to simulate language acquisition and sound change in a speech community. The simulation results provide plausible solutions that resolve some controversial issues regarding the sound change implementation such as the discrepancy between the Neogrammarian hypothesis and the lexical diffusion hypothesis. In the simulations, the patterns described by the two seemingly contradictory hypotheses both exist in the implementation of sound changes depending on the consistency of perceptual responses of the speakers in the population.